Turbine vane or blade.



' N0, 729,889.- PATENT-ED JUNE 2, 1903.

.T. PARKER.

TURBINE VANE 0R BLADE.

APPLICATION FILED JULY 23 1902.

N0 MODEL.

NITED STATES Patented June 2, 1902:.

PATENT OFFICE.

.TURB INE VANE OR BLADE.

SPECIFICATION forming part of Letters Patent No. 729,889, dated June 2,1903.

Application filed JnlyZS, 1902.

To all whom it may concern:

Be it known that I, THOMAS PARKER, a subject of the King of Great Britain, residing at 73 Lichfield street,\Volverhampton, county of Stafford, England, have invented a new and useful Improvement in Fixing Vanes or Blades, of which the following is a specification.

This invention relates to the fixing of vanes or blades to shafts, drums, cylinders, or disks, and in particular relates to the fixing of the vanes or blades in the drums and cylinders of steam-turbines.

In those machines wherein the moving parts are driven at a high rate of speed it is very important that projections attached to the periphery shall be firmly secured, so as to prevent them from flying outward under the action of centrifugal force. At the same time where a large number of such parts are required to be attached the securing means must be exceedingly simple and the attachment readily effected. In steam-turbines both of these conditions are required to be fulfilled, because in such engines there are a large number of blades which are fixed on a portion of the machine which rotates at ahigh speed, and said parts are required to be very accurately and firmly fixed in position.

According to the present invention I attain the object in view in a very simple and easy manner. The blades are fixed by their root or base portions in a dovetail circumferential groove formed on the shaft, drum, cylinder, or disk to which it is desired to attach the same, each blade being introduced through a slot substantially at right angles to and entering the circumferential groove. After the entire groove has been filled with blades, with the exception of that portion where the slot enters, the last blade is introduced through the slot and acts as a key for preventing circumferential movement of all the other blades and securely locks them in position. In order that the locking-blade shall itself be prevented from flying out through the action of centrifugal force, the slot through which the blades are introduced may be made either dovetailed in cross-section, or the sides of the outer portion may be radial, while-an extension of the slot toward theaxis is undercut,

Serial No. 116,631. (No model-l the locking-blade being provided with an extension of similar form fitting in the extension of the slot.

hen more than one row of blades is required, there will be, of course, a number of dovetailed circumferential grooves equal to that of the rows of blades desired, and a single slot may be provided running across and com municating with each groove, or in order to secure a better balance of "the parts when all the blades are in position short slots spaced equally apart at intervals and connecting adjacent grooves may be provided.

111 order that the invention maybe clearly understood, I will now proceed to explainthe same by the aid of the accompanying drawings, in which- Figure 1 is a transverse section through the axis of a drum provided with a single row of blades secured in accordance with my invention. Fig. 2 is an end view, partly in section, of the same, a number of the blades being omitted; and Fig. 3 is an end view of the drum without the blades.

1 is the drum, provided with a circumferential groove 2, which is of dovetail shape in cross-section, and 3 represents the blades, which are formed with bases 4, also of dovetail shape in cross-section, corresponding to the cross-section of the groove 2. The slot at right angles to the groove that is parallel with the axis of the drum is shown at 5, Fig. 3, and .is of such size as willpermit the blades to be passed in easily from the end face of the drum into the circumferential groove 2, in which they are all tightly packed. After the groove is filled with blades, with the exception of the part where it meets the slot 5, the lockingblade is inserted. This blade differs from the other blades in that its base is provided with an extension 6, which is of dovetail shape in cross-section and fits an extension of the slot 5. The shape of this blade is clearly shown in Fig. 2.

A band 7, of copper or other soft metal, may be placed around the bottom of the circumferential groove 2, and. this metal may be calked underneath each blade in order to press the base outward against the overhanging portion of the groove 2, or a wedge may be driven in between the base of each blade and the bottom of the groove for the same purpose. The locking-blade may be fixed in a similar manner by means of a strip of copper or other suitable metal placed in the bottom of the groove 5.

In place of the slot 5 being made deeper than the groove 2, as shown in Fig. 3, it may be made of the same depth, in which case the width of its mouth must be narrower than its width at the bottom-that is to say, the sides must overhang in order to provide 1' or securely holding the locking-blade in place. For example, the slot may have the same shape as the groove 2 in cross-section. In this case the base of the locking-blade will of course be shaped to correspond.

The groove 2 is not necessarily dovetailed in cross-section, as shown, but maybe of any suitable shape which will prevent the blades from flying outward under the action of centrifugal force. Two or more slots similar to the slot 5 maybe provided at intervals around the disk, if desired, in which case, of course, there will be a corresponding number of locking-blades.

In steam-turbines it is customary to provide several complete rings of blades on the same drmn, in which case a single slot, such as the slot 5, may be provided running the entire length of the drum, or the several grooves for the blades may connect with each other by short slots, which are placed at equal distances around the drum, so that the blades may be introduced from the end of said drum into any desired circumferential groove. By this-means the drum when completed is better balanced than when a single straight slot is employed. I

The drum may be of course built up of a number of disks each holding one ring of blades, said disks being angularly displaced with reference to each other, so that the locking-blades are staggered at equal intervals throughout the drum.

Blades may be fixed to the inside of a hollow cylinder in the same manner as that above described for the disk drum; but as such cylinders are usually made in two halves it is generally more convenient to' pass the blades direct into the required groove through the cut ends thereof, thus obviating the necessity for a longitudinal slot.

The invention is obviously applicable for fixing blades in the plane face of a disk, the manner of doing this requiring no further explanation.

The invention, although specially applicable to fixing the blades in steam-turbines, is not restricted to such use, as it may be applied generally to the fixing of radial blades or the like to shafts and cylinders for other purposessuch, for instance, as rotary aircompressors'.

IVhat I claim is 1. The combination with a solid of 1'evolu tion of a ring of blades, the bases of which are contained in a circumferential groove in the solid with undercut sides, and a lockingblade the base of which is received in the circumferential groove and the adj acentportions of a slot commiiinicating with said groove.

2. The combination of a solid of revolution, blades secured to the periphery thereof, the bases of said blades being received in a circumferential groove of a dovetailed shape in transverse section, and a locking-blade the base of which fills a portion of the circumferential groove and the adjacent parts of a slot which is also of a dovetailed shape in transverse section.

3. The combination of a solid of revolution with a ring of blades having their bases embedded in a circumferential groove with undercut sides, a strip of soft metal being interposed between the bases of the blades and the bottom of the groove and calked for the purposes of forcing the blades outward.

4. As a new article of manufacture a disk or drum provided with a circumferential groove having undercut sides for the reception of turbine-blades and a slot also having undercut sides communicating with said circumferential groove th rough which the blades may be introduced,substantially as described.

In testimony whereof I have hereunto subscribed my name this llth day of July, 1902.

THOMAS PARKER. lVitnesses:

MARTIN ALDERWIoK, HAROLD V ILLIERS -PEDLEY. 

